Gregor Fitzi is co-director of the Centre for Citizenship, Social Pluralism and Religious Diversity at University of Potsdam, Germany. After his PhD in Sociology at the University of Bielefeld, he was assistant professor at the Institute of Sociology, University of Heidelberg, Germany, and held a temporary position as full professor at the University of Bielefeld. His most recent publication is The Challenge of Modernity: Georg Simmel's Sociological Theory (Routledge, 2018). Jürgen Mackert is Professor of Sociology and co-director of the 'Centre for Citizenship, Social Pluralism and Religious Pluralism' at Potsdam University, Germany. His research interests are in sociology of citizenship, political economy, closure theory, collective violence. His most recent publication is The Transformation of Citizenship (Routledge, 2017), in three volumes, co-edited with Bryan S. Turner. Bryan S. Turner is Professor of the Sociology of Religion at the Australian Catholic University, Honorary Professor at Potsdam University and Honorary Fellow in The Edward Cadbury Centre, Birmingham University. In 2015 he received the Max Planck Award from the Max-Planck Society and Alexander von Humboldt Foundation, Germany. He is editor of Citizenship Studies, the Journal of Classical Sociology, and the Journal of Religious and Political Practice. He is also Chief Editor of the Wiley-Blackwell Encyclopedia of Social Theory (2017).
